Field of the Invention
The present invention relates to a sheet conveying apparatus configured to convey a single sheet or a bundle of sheets fed from, for example, an image forming apparatus. The present invention also relates to an image forming system including the sheet conveying apparatus.
Description of the Related Art
Hitherto, there have been provided image forming systems in which image forming apparatuses such as a copying machine, a printer, a facsimile machine, and a multifunction peripheral thereof are connected to post-processing apparatuses configured to perform various kinds of post-processing including sorting, aligning, binding, folding, and punching on sheets discharged from the image forming apparatuses. Those post-processing apparatuses are each configured to stack sheets from the image forming apparatuses on a processing tray, perform the post-processing, and then discharge the sheets onto a stacking tray.
As such a post-processing apparatus, there is known an apparatus having a buffering function to cause a succeeding sheet to temporarily remain on an upstream side of the processing tray so as to prevent the succeeding sheet from being conveyed to the processing tray where a preceding sheet undergoes post-processing, thus preventing the succeeding sheet from striking against the sheet during the post-processing or hindering the post-processing (see, for example, Japanese Patent Application Laid-Open No. 2004-269252). In the sheet processing apparatus described in Japanese Patent Application Laid-Open No. 2004-269252, a buffered succeeding sheet is overlaid on a post-processed sheet to be discharged onto the stacking tray from the processing tray with a slight displacement in a direction of discharge, and the sheets are integrally conveyed in a carry-out direction to cause the lower-side post-processed sheet to naturally fall on the stacking tray. After that, the succeeding sheet is conveyed in an opposite direction to be placed on the processing tray, thereby achieving further improvement of productivity.
In the conventional apparatus described in Japanese Patent Application Laid-Open No. 2004-269252, a post-processed sheet (or bundle of sheets) is caused to fall on the stacking tray under its own weight. Therefore, when the post-processed sheet and its succeeding sheet (or bundle of sheets) to be overlaid thereon are attracted to each other by static electricity, the post-processed sheet may adhere to the succeeding sheet and not be properly separated therefrom.